Heat Pumps: anyone have one/thought about it?

Heat pumps get a lot of negative press these days. Wonder why is that.

Theoretically gas is say 5p, electricity on night tariff is 7p. So if one can charge a home battery during the night and use that to power a heat pump it should be a lot cheaper than a boiler. As the boiler has say 90% efficiency and a heat pump maybe 300%.

So don't know why I'm hearing on radio all the time that heat pumps are a lot more expensive and not ready for prime time. Maybe my math is wrong. Or the oil and gas industry is very good at buying journalists.
 
Last edited:
Lots of people that just spread the nonsense they hear, without fully understanding it. There has also been numerous bad installs, chances are a bad gas install will still work fine, a bad heat pump install likely won't, its the design and installation at fault.

Saw a video the other day, new estate of 22 luxury really well spec'd houses, all with heat pumps, except they were all performing terribly, they were four times bigger than they needed to, and about four zones on an open plan ground floor it was never going to work well.

My own heat pump is cost 18p a day for hot water, I've got 29 kWh of battery storage, all refilled every day at 7p a kWh.
 
SkyTerran said:
Heat pumps get a lot of negative press these days. Wonder why is that.

Theoretically gas is say 5p, electricity on night tariff is 7p. So if one can charge a home battery during the night and use that to power a heat pump it should be a lot cheaper than a boiler. As the boiler has say 90% efficiency and a heat pump maybe 300%.

So don't know why I'm hearing on radio all the time that heat pumps are a lot more expensive and not ready for prime time. Maybe my math is wrong. Or the oil and gas industry is very good at buying journalists.
Click to expand...

Your math is wrong but not ‘that wrong’.

90% SCOP for a boiler is very generous and not at all typical.

300% SCOP for a heat pump is very pessimistic and lower than you would typically see.

The flaw in your logic is batteries are not free and you’ll never make your money back trying to save by running a heat pump on 100% off peak electricity.

I’ve got a heat pump, solar and batteries - have a look at my posts in this thread from me about batteries and time of use tariffs.
 
This post is an example, but I’ve posted other analysis of batteries and my own set up here before.

Heat Pumps: anyone have one/thought about it?

@b0rn2sk8 - I know you’ve mentioned it before but what’s your average energy use in kWh looking like for your heat pump (if you can separate it out from other usage)? And how big is your house? :p I’m looking at a new build with ASHP so trying to get a ballpark figure for usage, considering...
forums.overclockers.co.uk forums.overclockers.co.uk
 
SkyTerran said:
Heat pumps get a lot of negative press these days. Wonder why is that.

Theoretically gas is say 5p, electricity on night tariff is 7p. So if one can charge a home battery during the night and use that to power a heat pump it should be a lot cheaper than a boiler. As the boiler has say 90% efficiency and a heat pump maybe 300%.

So don't know why I'm hearing on radio all the time that heat pumps are a lot more expensive and not ready for prime time. Maybe my math is wrong. Or the oil and gas industry is very good at buying journalists.
Click to expand...

I genuinely don’t know. I wonder if it’s linked to a general dissatisfaction in the country looking to blame anything ‘new’ for all our woes without actually thinking about it. If people understand the tech’ and when it’s a good idea - then, they are a no-brainer. Like - really saved us a fortune in the 3 cold months we had it.
 
Anything green or to do with it (Solar, EVs, heat pumps, battery storage, smart meters) gets negative coverage, usually from a certain section of the press.

I too run my heat pump on cheap rate electricity from 2330-0500. I do the hot water heating (12p/day) and set to heat to 21C and run the heat pump hard during this time as I get 6p/kWh rate on my Octopus EV tariff. This is actually not the most efficient way to run (lower SCOP) but it's costing me much less this way. So far in May it's used about 48kWh for both combined but all was at 6p so it's £2.88 in total. Gas for the same would have been £11.69.

As above, I'll use some peak rate energy in winter but have 14.7kWh of battery storage so it shouldn't be too bad.

What you tend to find is that solar, EVs, batteries, heat pumps compliment each other which increase the savings. If done correctly they're excellent, but you'll always hear the stories when things haven't been done right.
 
Last edited:
  • Like
Reactions: Av8
reef said:
Anything green or to do with it (Solar, EVs, heat pumps, battery storage, smart meters) gets negative coverage, usually from a certain section of the press.

I too run my heat pump on cheap rate electricity from 2330-0500. I do the hot water heating (12p/day) and set to heat to 21C and run the heat pump hard during this time as I get 6p/kWh rate on my Octopus EV tariff. This is actually not the most efficient way to run (lower SCOP) but it's costing me much less this way. So far in May it's used about 48kWh for both combined but all was at 6p so it's £2.88 in total. Gas for the same would have been £11.69.

As above, I'll use some peak rate energy in winter but have 14.7kWh of battery storage so it shouldn't be too bad.

What you tend to find is that solar, EVs, batteries, heat pumps compliment each other which increase the savings. If done correctly they're excellent, but you'll always hear the stories when things haven't been done right.
Click to expand...
think your gas calculation is out slightly......gas is currently 5.12p on tracker, so less than your 6p leccy. so gas would be nowhere near 11.69 for 48kwh's
 
The Angry Welshman said:
think your gas calculation is out slightly......gas is currently 5.12p on tracker, so less than your 6p leccy. so gas would be nowhere near 11.69 for 48kwh's
Click to expand...
I was going by the standard rate, as that's what I've always been on. Even at that tracker rate it would be £8.60 for the gas vs £2.88 for the heat pump though.

It would be more than 48kWh of gas too remember, as I'm getting a COP of about 3.22 for heating/hot water combined and the boiler was 92% efficient (optimistic). It would be about 168kWh of gas.
 
Last edited:
The Angry Welshman said:
but you never said in your post that it was 168kwhs of gas, you just typed 48kwhs..... thats why i questioned your figures
Click to expand...
Yes, I should have been clearer maybe.

Essentially it has used 48kWh of electricity to generate 155kWh of heat. A gas boiler at around 92% efficiency would need to use 168kWh of gas to create the same amount of heat so its 48kWh x 6p vs 168kWh x 6.9p (or 5.12p on tracker).
 
Last edited:
92% is also extremely generous for a SCOP rating of a boiler.

There is bloody good reason why no manufacturer put performance meters on them :p

For the avoidance of doubt, it’s because none of them come close to the number on the side of the box in a typical U.K. domestic install.
 
My heat pump is 5.6 SCOP on heating, 5.3 on system. Add solar and no gas system gets near it.

To add. I pay a flat 15p per kWh of electricity with OVO for the heat pump use.
 
Last edited:
b0rn2sk8 said:
92% is also extremely generous for a SCOP rating of a boiler.

There is bloody good reason why no manufacturer put performance meters on them :p

For the avoidance of doubt, it’s because none of them come close to the number on the side of the box in a typical U.K. domestic install.
Click to expand...
You never see condensing boiler installations get panned because they run too hot to condense. Plus boilers could use weather dependant curves but the hardware is rarely installed. Too easy and cheap to just run them hot with small rads.
 
We had a Norsup heat pump installed some years ago to heat our indoor pool. Worked surprisingly very very well. We thought we'd need to top it up in the winter with the gas boiler, but actually it ran year round and kept the water nicely warm at around 27-30. Cost an absolute fortune though in electricity.

We've had it off for just under 2 years whilst doing some construction and extension. Finally got around to cleaning and refilling the pool, getting the pump etc all cleaned up and ready - turned the ASHP and the bugger is broken giving me a fault code. Some rubbish about the communication board. And because it's just over 5 years since installation it's out of warranty.

Back to the gas boiler it is.

Once I've got it fixed, I think I'll try to program it so it only runs between 23:30 and 05:30 (7p/kWh on Octopus Intelligent Go), and let the boiler run during the day time since gas is so much cheaper.
 
I'm still reading through all this from you guys, and all the posts I read about this that and the other I can't help but think sod it I won't bother. I'm struggling to win the mrs round full stop too us getting a ASHP, let alone following what everyone is saying from a negative view. Wife's argument, it won't pay for itself, my argument is neither does a lot of things in life.
Personally I want rid of the boiler and gas to the house, Electric only, and I am having solar and batteries done early next year 100% and the mrs isn't having a say in that at all.
 
Put the solar and battries in first, it will mean you 'win' the running costs argument. I'm spending about 1/4 of what I did on gas thanks to the solar, batteries and a time of use tarriff.

If you are paying price cap prices, the running costs are about the same. The install cost is what it is, someone has to bite the bullet once at some point.
 
b0rn2sk8 said:
Put the solar and battries in first, it will mean you 'win' the running costs argument. I'm spending about 1/4 of what I did on gas thanks to the solar, batteries and a time of use tarriff.

If you are paying price cap prices, the running costs are about the same. The install cost is what it is, someone has to bite the bullet once at some point.
Click to expand...

I agree, I am already on Octopus Intelligent Go, although for gas just recently fixed rate. But defo getting solar and batteries done as a priority.
 
You must log in or register to reply here.
Back
Top Bottom